Your Bolt sports a microSD memory card slot. If your laptop or personal computer is compatible with that card format (Most laptop computers are so-equipped), you should be able to transfer music files
The HTC Bolt is an Android smartphone and the Android market offers a bunch of free ringtone apps such as MP3 Ringtone Maker, Myxer and more.
Here is a sample of the free ringtones (compatible with your HTC Bolt) we offer:
Free Horror Ringtones Free Ghost Ringtones Free Short Ringtones Free Techno Ringtones Hear All Our Free Polyphonic Ringtones